The overall objectives of this proposal are to study the regulation of prostaglandin (PG) synthesis in cells from pulmonary blood vessels and parenchyma. Our working hypothesis for this project is that 1) PG production in each cell type from the lung is unique, 2) within the limits of this capability, extracellular effectors, drugs and the cellular milieu determine the quantity and type of PG a cell will produce 3) these environmental factors regulate cellular PG synthesis by influencing either lipase and/or cyclooxygenase-peroxidase actions and 4) cellular hydroperoxide levels, as they are maintained in each cell type, are an important determinant in these controls. Our specific aims are designed to test this working hypothesis. We will use pulmonary artery endothelial, smooth muscle and fibroblastic cells and parenchymal fibroblasts. Among methods to be applied are: Cell culture, Radioimmunoassay for PGs, Determination of cellular incorporation of labeled arachidonic acid, and its release from lipid stores and conversion to PGs and hydroxyacids (TLC) and Manipulation of cellular hydroperoxide levels.